The invention relates generally to systems for power pulse regulation and more particularly to such pulse regulation in systems with resonant charging of a pulse forming network. In various applications, an electrical power pulse having a high order of amplitude stability is required. This is particularly true of the transmitter-modulator pulses typical in pulsed radar systems. In such systems a power pulse of a few microseconds duration is typically generated at a pulse repetition frequency which may be fixed or variable. Such pulses are then applied to a microwave pulse generator such as a magnetron, or to an amplifier employing a travelling wave tube or the like, driven in a master oscillator-power amplifier configuration. The microwave pulse generators aforementioned are inherently sensitive to driving pulse amplitude and stability in respect to the frequency generated. In modern moving target indication radar systems, the stability of the microwave frequency is of particular importance, as is well-known to those of skill in the art.
Systems for regulating (stabilizing) the amplitude of repetitive power pulses generated by a resonant charging transmitter modulator are frequently called "de Quing" systems, and it is to such systems that the invention is particularly applicable. In such systems, the regulation of the pulse forming network of the system is usually undertaken by one means or another.
A prior art stabilization system is described in U.S. Pat. No. 4,371,830 (common assignee and inventorship vis-a-vis the invention). Although that system is relatively effective in reducing loss from dissipation of stored energy, it does not address the small, but important, variations of resonant charging peak amplitude.
Additional source of error in prior art systems are power supply ripple and the fact that the characteristic impedance of the pulse forming network does not continuously match the microwave generator load in frequency agile systems.
Direct regulation of the input power supply would be expected to be ideal, however such an arrangement is neither cost nor energy efficient. Moreover, design complications due to the high order of accuracy required (frequently at a relatively high voltage) tend to make direct regulation relatively unattractive.
Prior art systems usually dissipate a significant amount of energy, resulting in heat build-up and inefficient use of initial energy.
Since the charge current at the switching time flows through a charging choke and the pulse forming network, a significant amount of energy is stored in the network inductance. This energy represents an error signal randomly added to or subtracted from the network charge and is therefore a further source of output power pulse amplitude instability.
The manner in which the invention advances the art will be evident as this description proceeds.